I was looking into whether there would be any way to source propellants from the moon itself in support of a future base and space stations in cis-lunar space. I found two documents exploring how aluminum in particular might work in combination with liquid oxygen.
One is by Wickman Spacecraft & Propulsion, who say:
An additional option available with aluminum is to suspend the aluminum powder in gelled LOX to form a monopropellant... As part of our research, we made a small rocket engine fueled by the LOX-aluminum monopropellant... The propellant tank was surrounded by a liquid nitrogen bath to keep the LOX from boiling off. The propellant feed lines ran through a liquid nitrogen bath on their way to the combustion chamber. A piston pushed against the propellant to feed the propellant into the rocket engine chamber. While the thrust was only about a pound, the engine was started and stopped several times without a flashback of the combustion flame front into the propellant tank.
Aluminum and oxygen alone will provide a specific impulse somewhat lower than most hydrocarbons. Brower et al. expect a value of 285 seconds... One [engine design] would be to pump aluminum powder as we do fluids. In this case, it will probably be necessary to use a carrier gas along with the powder to keep the aluminum grains from vacuum welding or sticking together from electrostatic forces... Another technique is a hybrid rocket engine using solid aluminum and liquid oxygen. A conceptual design for such an engine was proposed by Brower et al. Their design calls for a hexagonal array of aluminum bars the length of the combustion chamber. Liquid oxygen would be fed down the bars for regenerative cooling before reaching the flame at the bar tips. The engine could use oxygen and aluminum only, or could use tripropellant operation with hydrogen.
The Brower et al. paper was presented at the 26th Joint Propulsion Conference in 1990 and is in the catalogue of the AIAA.
Obviously this needs a great deal of development, but at first blush it seems like it could have advantages over the usual proposal at this point - acquiring water ice from asteroids, or from permanently shaded craters at the moon's poles (if present in suitable quantities and concentrations), and splitting it into hydrogen and oxygen for use in H2/LOX engines.
The lunar highlands are composed largely of anorthite (CaAl2Si2O8), a mineral that is 15% aluminum and 62% oxygen. Regions that are 80% anorthite or more seem to be common. Extraction of oxygen has been discussed in a number of papers, it requires heating regolith above 1100 Celsius so that the mineral oxides dissociate and the oxygen can be collected.
Edit: I asked about this on the SE Chemistry community and got an answer from Jon Custer:
Fine powder feedstock... into an arc discharge to vaporize and ionize... electrostatic acceleration, then electromagnets to mass separate. Power with a solar panel array. No moving parts (except for the powder feed). No vacuum systems needed. And you separate all of the elements at once.
It has been pointed out to me by TildalWave that this would require a great deal of electricity and coolant. It occurred to me that perhaps the coolant could be avoided by putting the whole separator mechanism on rails, on a long shaded track running beside your solar panel field. If you set up the separator to dump the metal and slag products directly onto the ground under the track as it moves along, perhaps it is just a matter of figuring out how to get the flow and the rate at which the separator moves right, and the cooling could happen passively. There would be linear trails of metals and slag left on the ground which could slowly radiate away their heat until they are cool enough to be collected. There are probably reasons that wouldn't work, but I need to be told what they are. The oxygen that off-gasses could be collected from within the open-bottom chamber where the vaporized streams are ejected by the separator.
Could some process along these lines be competitive with asteroid mining? What are the issues and hurdles?